The invention is directed to a device for inservice monitoring of communication transmission equipment that contain at least one transmission link having two line terminal equipment between which one or more intermediate locations may be provided. Also provided is a monitoring unit that exchanges information via at least one telemetry channel with processor units that are allocated to monitored local ends and/or intermediate locations.
Such a device is already known from Ewald Braun and Erhard Steiner, "Supervision and Additional Services for Digital Fiber-Optic Transmission Systems" telcom report 10 (1987) Special "Multiplexing and Line Transmission", pages 107 through 112.
In the known device for in-service monitoring of a communication transmission equipment, useful signals are transmitted via an electrooptical transmission link and telemetry signals are transmitted via an auxiliary channel. The device uses address-free telemetry telegrams, so that the processor units provided in the line terminal equipment and intermediate repeaters of a transmission link need not be addressed. The method, however, cannot be employed without further ado in communication transmission equipment that have a star or, respectively, tree structure.